Exploring the Role of the Prefrontal Cortex in Decision-Making

Обзор

The goal of this study is to examine whether high-definition transcranial direct current stimulation (HD-tDCS) can influence decision-making for emotionally valenced content in younger and older adults, with or without major depression. The main questions are: In healthy adults, does brain stimulation modulate how people respond to emotionally valenced content during a decision-making task? What happens in the brain during modulation? Do these effects differ between younger and older adults? In adults with depression, does brain stimulation help shift attention towards positive content during the task? What happens in the brain? Are these effects moderated by age (younger vs. older adults)? The investigators will compare participants who receive real stimulation to those who receive sham (placebo) stimulation. Participants will: Receive high-definition transcranial direct current stimulation (HD-tDCS) of the dorsolateral prefrontal cortex (DLPFC) Perform a decision-making task involving emotionally valenced words Complete the task while undergoing a brain scan using ultra-high field 7 Tesla magnetic resonance imaging (MRI) to measure brain activity

Подробное описание

This study investigates whether non-invasive brain stimulation influences decision-making in four groups: younger adults (20-40 years) and older adults (60-75 years), healthy or with mild to moderate major depression. Participants with personality disorders or psychosis will be excluded.

The study builds on evidence that the dorsolateral prefrontal cortex (DLPFC) plays a key role in evaluating emotionally-valenced material and decision-making. The investigators will examine whether modulation of this region through high-definition transcranial direct current stimulation (HD-tDCS) affects responses to emotionally valenced information. Stimulation will be administered differently across groups based on theoretical models of hemispheric function in mood regulation.

To explore the effect of stimulation at neurotransmitter level, the investigators will use ultra-high field 7 Tesla magnetic resonance spectroscopy (MRS) to measure Gamma-aminobutyric acid (GABA) / Glutamate concentrations in regions of interest at baseline and after stimulation. This allows to examine whether changes in inhibitory/excitatory neurotransmitters are linked to altered emotional processing and decision making.

By combining brain stimulation, ultra-high field neuroimaging, and spectroscopy, this study examines how changes in brain network activity and neurotransmitter levels relate to decision-making in health and disease. The inclusion of both younger and older adults allows the investigators to explore age-related differences in these processes.

This project aims to provide mechanistic insights into decision-making in health and disease and to support the development of targeted neuromodulation therapies that could modulate emotional processing.

Вмешательства

• Устройство Active high-definition transcranial direct current stimulation (HD-tDCS) - anodal F3/F4
  Participants receive anodal HD-tDCS targeting the left or right DLPFC (F3/F4).
• Устройство Sham high-definition transcranial direct current stimulation (HD-tDCS) - anodal F3/F4
  Participants receive sham HD-tDCS targeting the left or right DLPFC (F3/F4). The device mimics the sensation of stimulation without delivering active current.
• Устройство Active high-definition transcranial direct current stimulation (HD-tDCS) - anodal F3/ kathodal F4
  Participants receive anodal HD-tDCS targeting the left DLPFC (F3) and cathodal stimulation targeting the right DLPFC (F4).
• Устройство Sham high-definition transcranial direct current stimulation (HD-tDCS) - anodal F3/ kathodal F4
  Participants receive sham HD-tDCS targeting the left DLPFC (F3) and right DLPFC (F4). The device mimics the sensation of stimulation without delivering active current.

Первичные конечные точки

• Blood-oxygen-level-dependent (BOLD) signal changes during task-based functional magnetic resonance imaging (fMRI) [Срок оценки: During study visit; measured continuously during the 20-minute stimulation period]
• GABA concentration (baseline) [Срок оценки: During study visit; during a 9-minute magnetic resonance spectroscopy (MRS) session performed up to 10 minutes prior to the 20-minute stimulation period]
• GABA concentration (after stimulation) [Срок оценки: During study visit; within 1 minute after the 20-minute stimulation period, during a 9-minute MRS scan]
• Glutamate concentration (baseline) [Срок оценки: During study visit; during a 9-minute magnetic resonance spectroscopy (MRS) session performed up to 10 minutes prior to the 20-minute stimulation period]
• Glutamate concentration (after stimulation) [Срок оценки: During study visit; within 1 minute after the 20-minute stimulation period, during a 9-minute MRS scan]

Вторичные конечные точки (6)

• Positive Affect measured by PANAS (baseline) [Срок оценки: During study visit; at baseline, up to two hours before the 20-minute stimulation period]
• Negative Affect measured by PANAS (baseline) [Срок оценки: During study visit; at baseline, up to two hours before the 20-minute stimulation period]
• Positive Affect measured by PANAS (after stimulation) [Срок оценки: During study visit; after stimulation, up to 1 hour]
• Negative Affect measured by PANAS (after stimulation) [Срок оценки: During study visit; after stimulation, up to 1 hour]
• Storytelling (baseline) [Срок оценки: During study visit; at baseline, up to two hours before the 20-minute stimulation period]
• Storytelling (after stimulation) [Срок оценки: During study visit; after stimulation, up to 1 hour]

Критерии участия

Inclusion Criteria (Healthy):

• Written Informed Consent
• Age between 20-40 or 60-75 years
• Fluent in German
• Normal or corrected-to-normal vision
• No color blindness
• Right-handed
• Non-smoker

Exclusion Criteria (Healthy):

• History of neurological disorders
• History of psychiatric disorders
• Use of psychotropic medication
• Presence of magnetizable implants
• Alcohol or drug dependence

Inclusion Criteria (Patient):

• Written Informed Consent
• Diagnosed with mild to moderate depression
• Age between 20-40 or 60-75 years
• Fluent in German
• Normal or corrected-to-normal vision
• No color blindness

Exclusion Criteria (Patient):

• Intake of benzodiazepines or antipsychotic medication
• psychiatric disorders other than depression (e.g., psychosis, mania, personality disorders) or depression with organic cause
• Presence of magnetizable implants
• Alcohol or drug dependence

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Да

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Двойное слепое

Основная цель

Фундаментальное исследование

Центры проведения

Швейцария · 1 центр

• University of Bern, Department of Old Age Psychiatry and Psychotherapy — Bern

Идентификаторы

NCT: NCT07080489 · 2024-01010

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

Открыть это исследование на ClinicalTrials.gov ↗